嵌入式学习-ARM

STM32串口控制三盏灯亮灭

MAIN.C

#include "uart4.h"
int main()
{uart4_init();gpio_init();char str[32];while (1){gets(str);if (my_strcmp(str,"A") == 0){led1();}else if (my_strcmp(str,"B") == 0){led2();}else if (my_strcmp(str,"C") == 0){led3();}puts(str);}return 0;
}

UART4.C

#include "uart4.h"void uart4_init()
{// 使能GPIOB GPIOP UART4RCC->MP_AHB4ENSETR |= (0x1);RCC->MP_AHB4ENSETR |= (0x1 << 6);RCC->MP_APB1ENSETR |= (0x1 << 16);// 设置PB2和PG11管脚复用GPIOB->MODER &= (~(0X3 << 4));GPIOB->MODER |= (0X1 << 5);GPIOG->MODER &= (~(0X3 << 22));GPIOG->MODER |= (0X1 << 23);GPIOB->AFRL &= (~(0XF << 8));GPIOB->AFRL |= (0X8 << 8);GPIOG->AFRH &= (~(0XF << 12));GPIOG->AFRH |= (0X6 << 12);// 设置串口不使能 UE=0USART4->CR1 &= (~(0X1));// 设置8位数据位USART4->CR1 &= (~(0X1 << 12));USART4->CR1 &= (~(0X1 << 28));// 设置没有奇偶校验位USART4->CR1 &= (~(0X1 << 10));// 设置1位停止位USART4->CR2 &= (~(0X3 << 12));// 设置16倍过采样USART4->CR1 &= (~(0X1 << 15));// 设置时钟不分频USART4->PRESC &= (~(0XF));// 设置波特率115200USART4->BRR &= (~(0XF));USART4->BRR |= (0X22b);// 使能发送器USART4->CR1 |= (0X1 << 3);// 使能接收器USART4->CR1 |= (0X1 << 2);// 使能uart4USART4->CR1 |= (0X1);
}void gpio_init()
{// GPIOE GPIOF时钟使能RCC->MP_AHB4ENSETR |= (0X3 << 4);// PE10 PF10 PE8设置为输出GPIOE->MODER &= (~(0X3 << 20));GPIOE->MODER |= (0X1 << 20);GPIOF->MODER &= (~(0X3 << 20));GPIOF->MODER |= (0X1 << 20);GPIOE->MODER &= (~(0X3 << 16));GPIOE->MODER |= (0X1 << 16);// 设置为推挽输出GPIOE->OTYPER &= (~(0X1 << 10));GPIOF->OTYPER &= (~(0X1 << 10));GPIOE->OTYPER &= (~(0X1 << 8));// 设置为低速输出GPIOE->OSPEEDR &= (~(0X3 << 20));GPIOF->OSPEEDR &= (~(0X3 << 20));GPIOE->OSPEEDR &= (~(0X3 << 16));// 设置为无上拉电阻GPIOE->PUPDR &= (~(0X3 << 20));GPIOF->PUPDR &= (~(0X3 << 20));GPIOE->PUPDR &= (~(0X3 << 16));// 默认低电平GPIOE->ODR &= (~(0X1 << 10));GPIOF->ODR &= (~(0X1 << 10));GPIOE->ODR &= (~(0X1 << 8));//GPIOE->ODR |= ((0X1 << 10));//GPIOF->ODR |= ((0X1 << 10));//GPIOE->ODR |= ((0X1 << 8));
}// 输出字符
void putchar(char a)
{// 先判断发送数据寄存器是否为空// 不为空阻塞等待// 为空向发送数据寄存器写入a的数据// 写入完成需要判断发送是否完成，不完成阻塞等待，完成了则函数结束while (!(USART4->ISR & (0X1 << 7)));USART4->TDR = a;while (!(USART4->ISR & (0X1 << 6)));
}// 获取字符
char getchar()
{// 先判断接收数据寄存器种有没有准备好的数据// 如果数据没有准备好则阻塞等到// 如果数据准备好了则读取// 读取完毕将读取到的数据返回while (!(USART4->ISR & (0X1 << 5))) // 等待数据;return USART4->RDR;
}// 获取字符串
void gets(char *str)
{while (1){*str = getchar();putchar(*str);    // 显示输入的字符if (*str == '\r') // 回车退出break;str++;}*str = '\0';putchar('\n'); // 换行
}// 输出字符串
void puts(char *s)
{while (*s){putchar(*s);s++;}putchar('\r');putchar('\n');
}void led1()
{if (GPIOE->ODR & (0X1 << 10)) // 此时是亮 改为暗GPIOE->ODR &= (~(0X1 << 10));else GPIOE->ODR |= (0X1 << 10);
}
void led2()
{if (GPIOF->ODR & (0X1 << 10)) // 此时是亮 改为暗GPIOF->ODR &= (~(0X1 << 10));else GPIOF->ODR |= (0X1 << 10);
}
void led3()
{if (GPIOE->ODR & (0X1 << 8)) // 此时是亮 改为暗GPIOE->ODR &= (~(0X1 << 8));else GPIOE->ODR |= (0X1 << 8);
}int my_strcmp(const char *src, const char *dest)
{while (*src == *dest){if (*dest == '\0')break;src++;dest++;}return *src - *dest;
}

UART4.H

#ifndef __UART4_H__
#define __UART4_H__#include "stm32mp1xx_uart.h"
#include "stm32mp1xx_gpio.h"
#include "stm32mp1xx_rcc.H"void uart4_init();
void gpio_init();
void putchar(char a);
char getchar();
void puts(char *s);
void gets(char *str);
void led1();
void led2();
void led3();
int my_strcmp(const char *src, const char *dest);#endif